Electromagnetic circuit-interrupter.



H. 0. Pun. ELEGTROMAGNET IC CIRCUIT INTERHUPTER'.

APPLICATION FILED D150. 28, I911.

Patented May 6, 1919.

2 SHEETS-SHEET I.

mwgnota Armafurt rimary 0/1101? [gm/iron Dgfiamo or Mag nefo.

awn/14430: fl: a Puii H. 0. PUIfI. ELECTROMAGNETIC CIRCUIT INTE RRUPTER. APPLICATION FILED DEC. 28. W17

To {gaff/on Dynamo or Magnefo.

Patented May 6, 1919;,

2 SHEETS-SHEET 2- .I-IAK'LIE 0. PUTT, OF ELKIEART, INDIANA.

ELECTROMAGNETIC C IRGUIT-INTEERFPTEE.

Specification of Letters Patent.

Application filed December 28, 1917. Serial No. 209,295.

To all whom it may concern:

Be it known that I, HARLIE 0. Porn a citizen of the United States, residing at Elkhart, in the county of Elkhart and State ot Indiana, have invented a new and useful Electromagnetic Circuit:Jnterrupter, of which the following is a specification.

The object of my invention is to provide a magnetically controlled and operated in terrupter which will automatically time itself to the peak of the primary current wave regardless of the direction of rotation or speed of magneto. It is also my object to provide an interrupter that may be installed at any point distant from the mag neto or ignition dynamo, such as the instrument board'of an automobile or aeroplane, thereby facilitating ease of inspection, adjustment or replacement, or it may be installed on the magneto itself at any convenient or desirable point.

I have primarily constructed this electromagnetic current interrupter to operate on the primary current of any ordinary high tension or compound wound magneto or ignition-dynamo armature, or on current from simple or single-wound armatures, although it 1s obvious that it will operate on a battery current if a suitable current contact controlling device'is mounted on and rotates *with the magneto armature shaft, so as to cause battery current to flow at or near the firing or ignition instant.

Its flexibility of installation, accessibility,

simplicity of principle and construction, efiiciency and accuracy of operation and low manufacturing cost, I regard of great value. Figure 1 is a front View of the interrupter partly in section;

Fig. 2 is a sectional view on the line 22 of Fig. 1; with a circuit diagram showing connections with condenser;

Fig. 3 is a plan view of the magnet pole laminae, showing general form. Like characters of reference designate like parts throughout the several views.

5 Referring to the accompanying drawings: The insulated contact screw terminal or post a, Fig. 1, carries an adjustable contact screw 2). The laminated pole pieces 0 and c project throughthe non-magnetic plate or' base (Z to which they are secured. The ,armature e of magnetic material is secured to a flat spring'g which is attached to lower pole piece 0 by means of screw h. This armature a. carries 5 two adjusting screws J and J which are adjusted in position by set screws K and K Contact arm L (which also acts as an armature) is also secured to spring 9 at the opposite end from that to which armature e is attached and carries a contact point at its other extremity. As illustrated, my armature e is of relatively heavier material than the second armature or contact arm L.

Adjusting screw J passes through a clear ance hole in armature or contact arm L and screws into armature e. The head of this screw strikes against arm L and acts as a stop for armature c in normal position.

Adjusting screw J threads through armature c to within a'short distance of armature or contact arm L and is locked in position by set screw K.

As illustrated in Fig. 2, I provide an elec tro-magnet coil m. and a core n of soft magnetic material rigidly attached to members 0 and 0 so as to, form a good magnetic connection with same.

The tension of spring g, Fig. l is such as .to pull armature c away from pole pieces points 10 causing poles 0 and 0 Fig. 1, to become magnetized they attract armature or contact arm L tending to cause contact points 39 to contact more firmly. At the same time armature e is attracted toward poles c and c and is free to move toward them'a definite degree or'distance without affecting contact arm L thereby gaining momentum before adjusting screw J strikes armature or contact arm L. When member J strikes armature or contact arm L it suddenly opens the primary circuit at contact points 19' and thereby deenergizes poles c and 0 Spring 9 then instantly returns armature e and contact arm L to normal position, as "shown in Fig. 1, ad]ust1ug screw J striking against contact arm L to firmly closecontact points p.

Patented May 6, 1919.

As the speed of the magneto increases, the consequent output or value of primary current increases, hence the pull or attractive force of poles will increase with the speed of the magneto. By providing the device 'shown in Fig. 1, I obtain automatic magnetic control of the tension of contact arm L in direct proportion to the strength of the primary current wave by the magnetic actlon on armature or contact arm L inasmuch as the stronger the poles c and 0 become,

. the more firmly does arm L hold contact points 7) closed. In other words, contact points p are caused to contact more firmly at high magneto speeds. By virtue of armature e being of heavier magnetic material,

- it still is strong enough to force arm L away from poles 0.

It is understood that the relative spring tension of contact arm L and armature e and also'the weight of their respective elements must be properly proportioned, but once adjusted, the adjustment remains permanent for'all speeds of magneto.

At low magneto speeds the armature 6 will lag, producing a somewhat retarded ignition spark. As the magneto speed increases, armature 6 acts with less lag thereby advancing the ignition spark. This advance and retardation is proportional to the speed of magneto within certain limits, but is autome-tic.

i As the magnetic attraction of the To illustrate the operation of my invention,'assume my structure is adjusted to respond to a current value of minimum degree. poles of the electi'o-magnet reaches a value suflicient to move the armature from its state of rest, or normal position, toward the poles of said magnet, the armature will lag behind the pull of the magnetto a certain degree,

because of the weight of this armature and the spring tension factor being so near the same value as the magnetic attractive factor. Also, a further degree of lag is caused by the natural reluctance of the core of the elecopening the circuit, of which the 'electromagnet is a part; The instant of break of the contacts will occur later than the instant of peak value oft-he current wave inducing the movement. This retardation is comparatively slight, however, but is of added value to the efficiency of the instrument, in that it effects a feature that is of value in gas. engine operation, namely automatic retardation at low engine speeds.

As the speed of the engine and magneto increases, the resultant primarv current value increases. of the magnet poles increase, which causes the.contact arm L to make afirmer contact with the fixed contact member, and also stiffening the action of the contact arm in relation to the armatuie, so that as the armature responds more quickly to the increased attractive force of the magnet poles, it attains greater momentum, and through the aforementioned adjusting screw, encounters a. less resilient contact arm, thereby obtaining a quicker break at the contact points. However, the resilient action of the armature or contact arm L in relation to the ar-- mature e-in returning to normal position or state of rest is effective, in'that it cush-.

ions the armature, which efl'ect makes it more readily responsive to the succeeding attractive effort, especially at high speed. The greater the degree of rigidity of armature or contact arm L as occasioned by the increased "magnetic action on same by the electromagnet, the greater the degree of rebound it will effecton'the armature; hence, the quicker will the armature attain its normal position, and consequently, through its connection with the contact arm, the quicker will the contact points he closed.

'To further increase the effectiveness of this factor and to offset the effect of residual magnetism in the poles of the electro-mag net, I projectthe poles c and a through non-magnetic disk or plate d, which in the structure illustrated in the drawings serves as a base or mounting for the instrument. This plate is preferablyof brass or other suitable material. At the instant of separa tion'of the contact points, a currentis in-- duced in this plate, which current flows in a direction around each magnet pole, tending to produce a magnetization of said poles of opposite polarity to'that of the polarity in-. duced by the primary current wave. This current induced in the plate only flows around the magnet poles for a period of time corresponding to the period of demagnetization of said poles, due to the opening of the circuit of which the electro -magnet is a part.

Hence the attractive force The effect is to completely eradicate any residual magnetism that may be momentarily present in the poles, and .through the repulsive action on the armature at this inis opposite to that of the electro-magnetic poles, but whenthe actual break'of contact points is effected, and for the instant, the

magnet poles reverse polarity, and the polarity being the same as that of the armature, the armature would be repulsed. Ihe armature, it will be understood, would be in closest proximity to the magnet poles at this instant, while the contact arm L would be relatively distant from them. Also the armature e is of sufficient weight and quality of material to enhance this magnetic inductive effect, while the contact arm L is so designed as to be practically unaliected by any repulsive efiect due to the nature and mass of its element, though the above-mentioned reversal of polarity of the magnet poles momentarily causes an attractive effort, though comparatively slight, of the contact arm L, which efi'ect is in co operation with the repulsive movement of the'armature 6.

At low magneto speeds the resultant residual magnetic factor would be comparatively less than at high magneto speeds, due to the variation of value in the primary current through the electromagnet coil. Also, the resultant inductive eiiect in the nonmagnetic plate around the magnet poles would be less due to the fact that the in tensity of magnetic flux in the poles would be less, but the armature would have more tim'e to get back to normal at the above men tion ed low magneto speeds.

All of the abovedescribed facts act in cooperation with the functional movement of applicants structure to secure the automatic adjustment of his structure to the variable values and frequencies of the current actuating same.

The self-induction of the electro-magnetic coil at the instant of the break of the circuit is completely absorbed or neutralized by the condenser (which. is connected across the break or point of contact in a manner familiar to those skilled in the art) as is also the self-induction of the whole primary circuit including the primary Winding on the magneto armature. This is necessary in order to prevent excessive arcing of the contact points at the instant of. break.

Tlie automatic timing of my structure to or nar the peak of the primary current wave of any standard high or low tension magneto on the market will be understood by the foregoing explanation.

It is understood that where a greater degree of advance and retardation'is required it must be acquired through some mechanical meansconnected between the magneto and the motor on which it is installed, or in other, words, by varying the position of the magneto armature in relation to the piston travel.

ployed does not close contacts quickly,

enough at high speed to insure saturation of the armature core with magnetic flux owing to the violence of the impact with the cam surface, which causes missing unless excessive spring tension is employed which rapidly wears both contact points and cam surfaces.

It will be seen that in my invention the degree of firmness of contact is increased proportionately with the magnetic strength of'poles c, Fig. 1, acting on contact arm or spring L and the magnetic strength of poles c is, of course, proportional to the speed of magneto, thereby securing an automatic adjustment.

In mechanically operated interrupters, the opening or" the contact points at low speed is necessarily slow. It extremely desirable to instantaneously open the contact points at all speeds, but at low speeds especially, in order to produce the maximum inductive effect in the magneto armature winding, thus generating a hotter and more efficient spark.

In my invention the rapidity or speed of interrupter at low magneto speeds is practically instantaneous in comparison with the speed of mechanically operated interrupters.

My invention is an improvement over prior mechanical circuit interrupters in that it may be installed at any point distant from the magneto or ignition dynamo, w .ere it may be more easily inspected, adjusted or replaced, as for example on'the instrument board of an automobile or aeroplane, instead of being attached to or (lID'QIl direct by some rotating or moving part of a magneto, such as the armature shaft, which would make rupter, the combination of a nonanagnetic plate, an electro-magnet having its poles projecting through the aforesaid plate, a spring secured to one'of the pole members, an armature of magnetic material secured to one end of the aforesaid s rin a contact arm secured to the other end of said spring, said contact aim'acting as an armature of lighter weight than the first mentioned armature, a Qcontact member with which the contact arm mentioned is arranged to elec tric'ally connect, means adjust-ably connecting the aforesaid contact arm and armature,

and an electric circuit electrically connected with the aforesaid apparatus and which is interrupted by the movement of the contact arm, substantially as described,

2. In an electro-magnetic circuit interrupter, the combinationof a non-magnetic inductive plate, an'electro-magnet having its poles projecting through said plate, a plurality of' armatures mounted in spaced relation to the poles of the magnet, means adj-ustably connecting the aforesaid armatures to maintain same in spaced relatlon as required, a contact member with which one of the armatures contacts, and an electric circuit electrically connected With the aforesaid apparatus and adapted to be interrupted by the movement of the armatures, substan tially as described.

3. In apparatus for interrupting an electric circuit, the combination of an electro magnet, an armature of relatively heavy material controlled by the electro-magnet, a

' second armature and contact member controlled by the beforementioned armature and electro-magnet, a non-magnetic inductive plate through Which the poles of the electro-magnet project, and an electric circuit electrically connected with the abovedescribed apparatus, said circuit being interrupted by the movement of the second armature and contact meniber, the operation of said last-mentioned member being automatically controlled by thegenerated or energizing current wave, substantially as described.

4. In an electro-magnetic circuit interrupter, the combination of an electr c circuit,

- a non-magnetic inductive plate, an electromagnet having its poles projecting through said plate, a plurality of armature members mounted in spaced relation to the poles of the magnet, means adjustably connecting poles of the magnet and'adapted to interrupt the electric circuit when the armature is attracted by the magnet, and means adjustably connectiif the aforesaid armature and contact mem'er, substantially as and for the purposes described. v,

6. An electro-magnetic circuit interrupter adapted to operate on a current of intermittent or alternating Values, comprising an elect-romagnet; laminated pole-pieces mounted on the magnet; a plurality of armatures supported in spaced relation from one pole o of said magnet; one of said armatures being of comparatively light resilient material and operating as a contact arm; means adjustably connecting relation; a non-magnetic inductive plate interposed between the electro-magnet coil and the aforesaid armatures; the aforesaid pole the aforesaid armatures to maintain same in the desired adjusted spaced pieces projecting through said plate to pro vide means to compensate the self-induction of the electro-magnetic coil, to eliminate the residual magnetism in the said poles of the electro-magnet, and to effect a repulsive effeet on the armature toward its normal position; and an electric circuit arranged substantially as described.

HARLIE o. PUTT. 

